Added TextHelper#strip_tags for removing HTML tags from a string (using HTMLTokenizer) (closes #2229) [marcin@junkheap.net]

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@2750 5ecf4fe2-1ee6-0310-87b1-e25e094e27de

actionpack/CHANGELOG

@@ -1,5 +1,7 @@
 *SVN*
 
+* Added TextHelper#strip_tags for removing HTML tags from a string (using HTMLTokenizer) #2229 [marcin@junkheap.net]
+
 * Added a reader for flash.now, so it's possible to do stuff like flash.now[:alert] ||= 'New if not set' #2422 [Caio Chassot]
 
 

actionpack/lib/action_view/helpers/text_helper.rb

@@ -202,6 +202,28 @@ module ActionView
         html
       end
       
+      # Strips all HTML tags from the input, including comments.  This uses the html-scanner
+      # tokenizer and so it's HTML parsing ability is limited by that of html-scanner.
+      #
+      # Returns the tag free text.
+      def strip_tags(html)
+        if html.index("<")
+          text = ""
+          tokenizer = HTML::Tokenizer.new(html)
+
+          while token = tokenizer.next
+            node = HTML::Node.parse(nil, 0, 0, token, false)
+            # result is only the content of any Text nodes
+            text << node.to_s if node.class == HTML::Text  
+          end
+          # strip any comments, and if they have a newline at the end (ie. line with
+          # only a comment) strip that too
+          text.gsub(/<!--(.*?)-->[\n]?/m, "") 
+        else
+          html # already plain text
+        end 
+      end
+      
       # Returns a Cycle object whose to_s value cycles through items of an
       # array every time it is called. This can be used to alternate classes
       # for table rows:

actionpack/test/template/text_helper_test.rb

@@ -268,4 +268,13 @@ class TextHelperTest < Test::Unit::TestCase
     assert_equal(%w{Specialized Fuji Giant}, @cycles)
   end
 
+  def test_strip_tags
+    assert_equal("This is a test.", strip_tags("<p>This <u>is<u> a <a href='test.html'><strong>test</strong></a>.</p>"))
+    assert_equal("This is a test.", strip_tags("This is a test."))
+    assert_equal(
+    %{This is a test.\n\n\nIt no longer contains any HTML.\n}, strip_tags(
+    %{<title>This is <b>a <a href="" target="_blank">test</a></b>.</title>\n\n<!-- it has a comment -->\n\n<p>It no <b>longer <strong>contains <em>any <strike>HTML</strike></em>.</strong></b></p>\n}))
+    assert_equal("This has a  here.", strip_tags("This has a <!-- comment --> here."))
+  end
+
 end